pub enum MaybeCause {
Ambiguity,
Overflow {
suggest_increasing_limit: bool,
},
}
Expand description
Why we failed to evaluate a goal.
Variants§
Ambiguity
We failed due to ambiguity. This ambiguity can either
be a true ambiguity, i.e. there are multiple different answers,
or we hit a case where we just don’t bother, e.g. ?x: Trait
goals.
Overflow
We gave up due to an overflow, most often by hitting the recursion limit.
Trait Implementations§
§impl Clone for MaybeCause
impl Clone for MaybeCause
§fn clone(&self) -> MaybeCause
fn clone(&self) -> MaybeCause
Returns a copy of the value. Read more
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from
source
. Read more§impl Debug for MaybeCause
impl Debug for MaybeCause
§impl Hash for MaybeCause
impl Hash for MaybeCause
§impl<__CTX> HashStable<__CTX> for MaybeCause
impl<__CTX> HashStable<__CTX> for MaybeCause
fn hash_stable( &self, __hcx: &mut __CTX, __hasher: &mut StableHasher<SipHasher128>, )
§impl PartialEq for MaybeCause
impl PartialEq for MaybeCause
§fn eq(&self, other: &MaybeCause) -> bool
fn eq(&self, other: &MaybeCause) -> bool
This method tests for
self
and other
values to be equal, and is used
by ==
.§impl<I> TypeFoldable<I> for MaybeCausewhere
I: Interner,
impl<I> TypeFoldable<I> for MaybeCausewhere
I: Interner,
§fn try_fold_with<F>(
self,
_: &mut F,
) -> Result<MaybeCause, <F as FallibleTypeFolder<I>>::Error>where
F: FallibleTypeFolder<I>,
fn try_fold_with<F>(
self,
_: &mut F,
) -> Result<MaybeCause, <F as FallibleTypeFolder<I>>::Error>where
F: FallibleTypeFolder<I>,
§fn fold_with<F>(self, _: &mut F) -> MaybeCausewhere
F: TypeFolder<I>,
fn fold_with<F>(self, _: &mut F) -> MaybeCausewhere
F: TypeFolder<I>,
A convenient alternative to
try_fold_with
for use with infallible
folders. Do not override this method, to ensure coherence with
try_fold_with
.§impl<I> TypeVisitable<I> for MaybeCausewhere
I: Interner,
impl<I> TypeVisitable<I> for MaybeCausewhere
I: Interner,
§fn visit_with<F>(&self, _: &mut F) -> <F as TypeVisitor<I>>::Resultwhere
F: TypeVisitor<I>,
fn visit_with<F>(&self, _: &mut F) -> <F as TypeVisitor<I>>::Resultwhere
F: TypeVisitor<I>,
impl Copy for MaybeCause
impl Eq for MaybeCause
impl StructuralPartialEq for MaybeCause
Auto Trait Implementations§
impl DynSend for MaybeCause
impl DynSync for MaybeCause
impl Freeze for MaybeCause
impl RefUnwindSafe for MaybeCause
impl Send for MaybeCause
impl Sync for MaybeCause
impl Unpin for MaybeCause
impl UnwindSafe for MaybeCause
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§default unsafe fn clone_to_uninit(&self, dst: *mut T)
default unsafe fn clone_to_uninit(&self, dst: *mut T)
🔬This is a nightly-only experimental API. (
clone_to_uninit
)source§impl<T> CloneToUninit for Twhere
T: Copy,
impl<T> CloneToUninit for Twhere
T: Copy,
source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
🔬This is a nightly-only experimental API. (
clone_to_uninit
)§impl<T, R> CollectAndApply<T, R> for T
impl<T, R> CollectAndApply<T, R> for T
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
Compare self to
key
and return true
if they are equal.source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
Converts
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
Converts
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§impl<T> Pointable for T
impl<T> Pointable for T
§impl<I, T> TypeVisitableExt<I> for Twhere
I: Interner,
T: TypeVisitable<I>,
impl<I, T> TypeVisitableExt<I> for Twhere
I: Interner,
T: TypeVisitable<I>,
fn has_type_flags(&self, flags: TypeFlags) -> bool
§fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_at_or_above(&self, binder: DebruijnIndex) -> bool
Returns
true
if self
has any late-bound regions that are either
bound by binder
or bound by some binder outside of binder
.
If binder
is ty::INNERMOST
, this indicates whether
there are any late-bound regions that appear free.fn error_reported(&self) -> Result<(), <I as Interner>::ErrorGuaranteed>
§fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
fn has_vars_bound_above(&self, binder: DebruijnIndex) -> bool
Returns
true
if this type has any regions that escape binder
(and
hence are not bound by it).§fn has_escaping_bound_vars(&self) -> bool
fn has_escaping_bound_vars(&self) -> bool
Return
true
if this type has regions that are not a part of the type.
For example, for<'a> fn(&'a i32)
return false
, while fn(&'a i32)
would return true
. The latter can occur when traversing through the
former. Read morefn has_aliases(&self) -> bool
fn has_inherent_projections(&self) -> bool
fn has_opaque_types(&self) -> bool
fn has_coroutines(&self) -> bool
fn references_error(&self) -> bool
fn has_non_region_param(&self) -> bool
fn has_infer_regions(&self) -> bool
fn has_infer_types(&self) -> bool
fn has_non_region_infer(&self) -> bool
fn has_infer(&self) -> bool
fn has_placeholders(&self) -> bool
fn has_non_region_placeholders(&self) -> bool
fn has_param(&self) -> bool
§fn has_free_regions(&self) -> bool
fn has_free_regions(&self) -> bool
“Free” regions in this context means that it has any region
that is not (a) erased or (b) late-bound.
fn has_erased_regions(&self) -> bool
§fn has_erasable_regions(&self) -> bool
fn has_erasable_regions(&self) -> bool
True if there are any un-erased free regions.
§fn is_global(&self) -> bool
fn is_global(&self) -> bool
Indicates whether this value references only ‘global’
generic parameters that are the same regardless of what fn we are
in. This is used for caching.
§fn has_bound_regions(&self) -> bool
fn has_bound_regions(&self) -> bool
True if there are any late-bound regions
§fn has_non_region_bound_vars(&self) -> bool
fn has_non_region_bound_vars(&self) -> bool
True if there are any late-bound non-region variables
§fn has_bound_vars(&self) -> bool
fn has_bound_vars(&self) -> bool
True if there are any bound variables
§fn still_further_specializable(&self) -> bool
fn still_further_specializable(&self) -> bool
Indicates whether this value still has parameters/placeholders/inference variables
which could be replaced later, in a way that would change the results of
impl
specialization.§impl<I, T> UpcastFrom<I, T> for T
impl<I, T> UpcastFrom<I, T> for T
fn upcast_from(from: T, _tcx: I) -> T
source§impl<T> WithSubscriber for T
impl<T> WithSubscriber for T
source§fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
source§fn with_current_subscriber(self) -> WithDispatch<Self>
fn with_current_subscriber(self) -> WithDispatch<Self>
impl<'a, T> Captures<'a> for Twhere
T: ?Sized,
Layout§
Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...)
attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.
Size: 1 byte
Size for each variant:
Ambiguity
: 0 bytesOverflow
: 1 byte